The Device-to-Device (D2D) communication is a new-type technology that allows directly performing communication by multiplexing intra-cell resources between terminals under the control of the cellular system. The D2D technology has advantages including improving system spectrum efficiency, reducing battery consumption of the terminal so as to save power of the mobile station, lowering load of the base station of the cellular cell, improving the user fairness of the system, enhancing the quality of network service, consolidating the substructure and providing new services and so on; and it can solve the problem of channel resource shortage of the wireless communication system to a certain degree.
The D2D communication between users may not only occur within the same operator, but also occur between different operators. In either case, there may be certain problems when it is to achieve the D2D communication, for example, how to allocate channel resources occupied by the D2D user communication, and how to coordinate the D2D communication between the operators and so on.
FIG. 1 is a structural diagram of achieving the D2D communication at present, as shown in FIG. 1, users in the D2D communication are a user equipment A (UE-A), a UE-B and a UE-C respectively. The UE-A is controlled by a base station A (S-A), the UE-B is controlled by a base station S-B, and the UE-C is controlled by a base station S-C; wherein, the A, B and C may belong to different operators, or they may belong to the same operator. At present, generally channel resources occupied by the D2D communication are allocated by a base station side of a cell where an initiator is located. However, once the initiator is in channel resource shortage, for example, there are no spare channel resources or no appropriate shared channel resources and so on, the D2D users are normally required to hand over to the cellular network communication from the D2D communication, so that the D2D communication undoubtedly loses the function of relieving the channel resource shortage of the wireless communication system, thereby increasing the burden of the cellular network, and reducing the resource utilization rate of the cellular network.